Explain why the read-committed isolation level ensures that schedules are cascade-free.

For mutual exclusion with a preemptive scheduler, it is necessary to introduce explicit locks, and machinery that makes requesting processes wait when a lock is unavailable. We considered casting our locks as semaphores, but decided that, compared with monitors, they exert too little structuring discipline on concurrent programs." How do semaphores "exert too little structuring discipline" and how is this remedied by monitors? Construct an example to show how the structuring discipline exerted by monitors could be useful.

Suppose there are four processes (P1 - P4) with respective arrival times of 0, 10, 30, and 40, and burst times of 30, 20, 50, and 20 ms. These processes are scheduled from a ready queue on first come first served. The average waiting time is?

On a computer system with one processor (CPU), and N (N> 1) processes present in the system, what is the maximum number of processes that can be in the Running, and in the Blocked states at any given time? Assume 5-state model for process states.

The access-control matrix could be used to determine whether a process can switch from, say, domain A to domain B and enjoy the access privileges of domain B. Is this approach equivalent to including the access privileges of domain B in those of domain A?

Explain why redo is carried out in a forward manner while undo log data must be handled in reverse order.

What is the concept of a deadlock-free state, and how can it be achieved in a multi-process environment?

Consider a system consisting of four resources of the same type that are shared by three processes, each of which needs at most two resources. Show that the system is deadlock free.

Draw a precedence network for 3 activities: A, B, and C; with durations of 9, 4, and 7 days; respectively, and connected with SS and FF relationships. Put a 2-day lag on every SS relationship and a 1-day lag on every FF relationship. Do the CPM calculations and mark the critical path: assuming that all activities are contiguous assuming that all activities are interruptible a- b-

Can deadlock prevention and avoidance be distinguished?